Spring treat, say, including special rates for one (6,3)
I believe the answer is:
easter egg
'spring treat' is the definition.
'easter egg' can be an answer for 'treat' (I have seen 'seasonal treat' mean 'easter egg' so perhaps 'treat' could also mean 'easter egg'). I'm not sure about the 'spring' bit.
'say including special rates for one' is the wordplay.
'say' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'including' indicates putting letters inside.
'special' is an anagram indicator.
'for one' becomes 'eg' (both can mean 'for example').
'rates' is an anagram of 'aster'.
'aster'+'eg'='astereg'
'eg' going around 'astereg' is 'EASTER EGG'.
Can you help me to learn more?
(Other definitions for easter egg that I've seen before include "Sweet for Spring festival" , "DVD bonus" , "Segregate from traditional chocolate ovum" , "Candy to celebrate Spring festival" , "Seasonal present" .)